What is data recovery?
Data recovery is the process of retrieving data from a device that has failed, where data is inaccessible, has been deleted or corrupted. Data recovery can be attempted on all data bearing devices, most commonly this is hard disk drives or chip based devices such as SSDs, USB memory stick or other memory cards.
It can be a simple process such as recovering lost or deleted files or more complex such as a mechanically failed drive in a multi disk RAID system.
Data recovery falls into two categories determined by logical or physical damage.
For devices with logical damage, specialist data recovery software is used to access the data. This could be relatively straight forward such as finding deleted files, or something more complex like simulating a piece of hardware to communicate with the damaged device.
Devices with physical damage may require the use of software techniques, but often need engineering intervention to recover the data. Repairing circuit boards, replacing electronic components and micro-soldering is common across all types of device. The data recovery process aims to fix the damaged device enough to enable the data to be copied onto a new working device.
Some types of device require the replacement of parts to enable access to the data. It is not uncommon to replace the entire read/write head assembly in hard disk drives. Chip level recovery can be performed on severely damaged PCB based devices, where the entire chip is removed from the board and directly accessed by external software.
Hard drive recoveries where the outer casing is opened need to be done in an air filtered clear environment to ensure no dust particles land on the surface of the disk platter. The read write heads of a hard drive float between 3-6 nanometres (1,000,000 in a millimetre) above the disk surface. If these read/write heads contact any such particles it can easily cause damage to the disk surface, making the data unrecoverable.